THIS invention relates to a method of and a system for estimating sensible heat flux and hence evaporation representative of an area substantially in real-time for example sub-hourly. The invention also relates to a datalogger device and a data-logging kit for estimating evaporation.
Evaporation is a key component of the water balance at the Earth's surface. While its determination is important for water resource management, evaporation is seldom measured directly and usually inferred from other measurements. For example, data from an automatic weather station allow grass reference evaporation and tall-crop reference evaporation to be estimated in near real-time. The disadvantage of this method is that a crop factor (K) is required to calculate offline the actual evaporation: actual evaporation=K×grass reference evaporation. The crop factor varies with crop type, stage of crop growth and management practice(s).
Other methods and/or systems to determine evaporation are computationally intensive and do not allow or provide for near real-time estimation of evaporation. Also, other methods and/or systems to determine evaporation are prohibitively expensive, are high maintenance, or require specialised skills to operate.
A need exists for an inexpensive, low-power and reasonably accurate system that allows sub-hourly estimates of evaporation and does not require calibration.
It is an object of the present invention at least to address the abovementioned problems and need.